342 SCIENCE PROGRESS. 



may be such that there is, as regards water, a balance be- 

 tween the " physiological " absorbing force and the osmotic 

 pressure. Salt, however, will, under such conditions, con- 

 tinue to diffuse into the blood, and as the osmotic pressure 

 in the tube of the gut is thereby lowered, at a later period, 

 as the incoming osmotic stream of water wanes, it becomes 

 more and more swamped by the opposing "physiological" 

 current. 



" So bewirkt die physikalische Diffusion fur die physio- 

 logische Triebkraft Befreiung von den Fesseln, welche zu 

 hohe endosmotische Spannung des Darminhaltes ihr anlegte, 

 indem sie diese Spannung vermindert." 



Turning now to the case oi "weak" solutions of sodic 

 chloride ('3 to "5 per cent.), i.e., solutions with a lower per- 

 centage than the blood, we see that "physically" water 

 must pass to the blood with its higher osmotic pressure of 

 salt, and salt should diffuse into the gut ; but since here, 

 again, there is a " physiological ' output of salt and water, 

 and since the actual experiments show that salt really dis- 

 appears from the gut, the "physical' salt stream must be 

 swamped by that of " physiological " origin. 



In the case, then, of " weak ' solutions as contrasted 

 with " strong," the salt absorption is purely " physiological," 

 the water absorption partly " physical " and partly " physio- 

 logical ". 



There are then three distinct reasons for the hypothesis 

 of a " physiological " action in the absorption of salt solu- 

 tions : — 



1. Fluids with the same total osmotic pressure as the 

 blood are rapidly absorbed. 



2. Water enters the blood from sodic chloride solutions 

 in the gut, whose osmotic pressure exceeds that of the 

 blood. 



3. Salt enters the blood from sodic chloride solutions in 

 the gut, whose partial pressure in sodic chloride is less than 

 that in the blood. 



The results of diminishing the physiological " trieb- 

 kraft " will be different in the case of the absorption of the 

 " strong " and the " weak " solutions. 



